Surplus electricity from cellphone towers can run

STAFF at Morganster Hospital, which serves a
remote community in Zimbabwe's Masvingo province[1], used
to sleep fitfully. If the power failed and a back-up generator was
offline - common problems in the impoverished nation - they would
have to jump out of bed and drive for 26 kilometres to stash their
stock of life-saving vaccines in a fridge in the provincial
capital.

But those days are over, thanks to a pilot
project that is testing
a simple idea floated in the pages of New Scientist[2]. In
that article, infectious disease specialist Harvey
Rubin[3] of the University of Pennsylvania in Philadelphia and
Alice Conant, then a student at Harvey Mudd College in Claremont,
California, suggested using surplus power from cellphone towers to
run the refrigerators needed to keep perishable vaccines cool (18
September 2010, p 24).

Their idea is now being tried out at 10
church-run hospitals across Zimbabwe, with the backing of Econet Wireless[4], a
cellphone provider based in Johannesburg, South Africa. After
Bernard Fernandes, Econet's chief technology officer, heard Rubin
give a presentation in Mombasa, Kenya, in March 2011, he went
straight to Econet's chairman, Strive
Masiyiwa[5], with a proposal. "He said to me: 'Get on with it',"
Fernandes says.

Cellphones have overtaken landlines in developing
countries. To keep their towers working reliably in areas where the
power often fails, or the masts are off the grid, cellphone firms
have installed generators, and sometimes solar panels. Surplus
power can then be used to chill vaccines, maintaining the cold
chain, the weakest link in efforts to immunise children against
diseases like polio, measles and diphtheria.

To be sure that power glitches wouldn't cause
problems, Fernandes chose fridges by True
Energy[6] of Tywyn, UK, that can keep cool for 10 days without
power, even in temperatures above 40 °C. The fridges have
sensors to monitor temperature both inside and out, and to detect
when the door is opened. This data is relayed back via the
cellphone network, allowing Econet and its partners to know
immediately if anything goes wrong. The fridges are either housed
in a shelter beneath the cellphone tower, or in the hospital if it
is nearby.

Several other projects are in the planning
stages. In India, Rubin's non-profit organisation, Energize the Chain[7], is
talking to the Vodafone
Foundation[8] and the Karuna Trust[9], which is known for
its work in providing healthcare to the "untouchable" Dalit caste.
This initiative would include a controlled experiment to confirm if
sites powered by cellphone towers have less vaccine spoilage. This
is easy to check because vials of vaccine can be fitted with labels[10]
that darken on exposure to heat. Meanwhile in Kenya, Energize the
Chain hopes to launch a pilot project involving 10 or more sites,
with the backing of both the Kenyan and US governments.

Anthony Battersby, a consultant based near Bath,
UK, who conducted a feasibility study for the Kenyan project,
worries that high-tech fridges might fail, and so has proposed
making ice at the cellphone towers instead, then moving it to
coolers in clinics.

Rubin says he doesn't mind which technology is
used, as long as vaccines are kept cool and more children get
immunised. "What's remarkable is the rapidity with which the idea
has been picked up," he says.